/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model;

import java.util.List;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;
import net.sf.freecol.common.util.Utils;

import org.w3c.dom.Element;


/**
 * The <code>Modifier</code> class encapsulates a bonus or penalty
 * that can be applied to any action within the game, most obviously
 * combat. The Modifier may be applicable only to certain Objects
 * specified by means of <code>Scope</code> objects.
 */
public class Modifier extends Feature
{

    public static final String AMPHIBIOUS_ATTACK
            = "model.modifier.amphibiousAttack";
    public static final String ARTILLERY_AGAINST_RAID
            = "model.modifier.artilleryAgainstRaid";
    public static final String ARTILLERY_IN_THE_OPEN
            = "model.modifier.artilleryInTheOpen";
    public static final String ATTACK_BONUS
            = "model.modifier.attackBonus";
    public static final String BIG_MOVEMENT_PENALTY
            = "model.modifier.bigMovementPenalty";
    public static final String BOMBARD_BONUS
            = "model.modifier.bombardBonus";
    public static final String BREEDING_DIVISOR
            = "model.modifier.breedingDivisor";
    public static final String BREEDING_FACTOR
            = "model.modifier.breedingFactor";
    public static final String BUILDING_PRICE_BONUS
            = "model.modifier.buildingPriceBonus";
    public static final String CARGO_PENALTY
            = "model.modifier.cargoPenalty";
    public static final String COLONY_GOODS_PARTY
            = "model.modifier.colonyGoodsParty";
    public static final String CONSUME_ONLY_SURPLUS_PRODUCTION
            = "model.modifier.consumeOnlySurplusProduction";
    public static final String CONVERSION_ALARM_RATE
            = "model.modifier.conversionAlarmRate";
    public static final String CONVERSION_SKILL
            = "model.modifier.conversionSkill";
    public static final String DEFENCE
            = "model.modifier.defence";
    public static final String EXPLORE_LOST_CITY_RUMOUR
            = "model.modifier.exploreLostCityRumour";
    public static final String EXPOSED_TILES_RADIUS
            = "model.modifier.exposedTilesRadius";
    public static final String FORTIFIED
            = "model.modifier.fortified";
    public static final String IMMIGRATION
            = "model.modifier.immigration";
    public static final String LAND_PAYMENT_MODIFIER
            = "model.modifier.landPaymentModifier";
    public static final String LIBERTY
            = "model.modifier.liberty";
    public static final String LINE_OF_SIGHT_BONUS
            = "model.modifier.lineOfSightBonus";
    public static final String MINIMUM_COLONY_SIZE
            = "model.modifier.minimumColonySize";
    public static final String MISSIONARY_TRADE_BONUS
            = "model.modifier.missionaryTradeBonus";
    public static final String MOVEMENT_BONUS
            = "model.modifier.movementBonus";
    public static final String NATIVE_ALARM_MODIFIER
            = "model.modifier.nativeAlarmModifier";
    public static final String NATIVE_CONVERT_BONUS
            = "model.modifier.nativeConvertBonus";
    public static final String OFFENCE
            = "model.modifier.offence";
    public static final String OFFENCE_AGAINST
            = "model.modifier.offenceAgainst";
    public static final String PEACE_TREATY
            = "model.modifier.peaceTreaty";
    public static final String POPULAR_SUPPORT
            = "model.modifier.popularSupport";
    public static final String RELIGIOUS_UNREST_BONUS
            = "model.modifier.religiousUnrestBonus";
    public static final String SAIL_HIGH_SEAS
            = "model.modifier.sailHighSeas";
    public static final String SHIP_TRADE_PENALTY
            = "model.modifier.shipTradePenalty";
    public static final String SMALL_MOVEMENT_PENALTY
            = "model.modifier.smallMovementPenalty";
    public static final String SOL
            = "model.modifier.SoL";
    public static final String TILE_TYPE_CHANGE_PRODUCTION
            = "model.modifier.tileTypeChangeProduction";
    public static final String TRADE_BONUS
            = "model.modifier.tradeBonus";
    public static final String TRADE_VOLUME_PENALTY
            = "model.modifier.tradeVolumePenalty";
    public static final String TREASURE_TRANSPORT_FEE
            = "model.modifier.treasureTransportFee";
    public static final String WAREHOUSE_STORAGE
            = "model.modifier.warehouseStorage";

    public static final float UNKNOWN = Float.MIN_VALUE;

    public static final int DEFAULT_MODIFIER_INDEX = 0;

    // @compat 0.10.x
    // These are now attached to modifiers in the spec, but
    // Specification.fixup010x() still needs them for now.
    public static final int RESOURCE_PRODUCTION_INDEX = 10;
    public static final int COLONY_PRODUCTION_INDEX = 20;
    public static final int EXPERT_PRODUCTION_INDEX = 30;
    public static final int FATHER_PRODUCTION_INDEX = 40;
    public static final int IMPROVEMENT_PRODUCTION_INDEX = 50;
    public static final int AUTO_PRODUCTION_INDEX = 60;
    public static final int BUILDING_PRODUCTION_INDEX = 70;
    public static final int NATION_PRODUCTION_INDEX = 80;
    public static final int PARTY_PRODUCTION_INDEX = 90;
    public static final int DISASTER_PRODUCTION_INDEX = 100;
    // end @compat 0.10.x
    public static final int DEFAULT_PRODUCTION_INDEX = 100;

    // Specific combat indicies
    public static final int BASE_COMBAT_INDEX = 10;
    public static final int UNIT_ADDITIVE_COMBAT_INDEX = 20;
    public static final int UNIT_NORMAL_COMBAT_INDEX = 40;
    public static final int ROLE_COMBAT_INDEX = 30;
    public static final int GENERAL_COMBAT_INDEX = 50;

    public static enum ModifierType
    {
        ADDITIVE,
        MULTIPLICATIVE,
        PERCENTAGE
    }

    /** The type of this Modifier. */
    private ModifierType modifierType;

    /** The value of this Modifier. */
    private float value;

    /**
     * The value increments per turn.  This can be used to create
     * Modifiers whose values increase or decrease over time.
     */
    private float increment;

    /** The type of increment. */
    private ModifierType incrementType;

    /** A sorting index. */
    private int modifierIndex = DEFAULT_MODIFIER_INDEX;


    /**
     * Deliberately empty constructor.
     */
    protected Modifier( ) {}

    /**
     * Use this only for reading from DOM Elements.
     *
     * @param specification The <code>Specification</code> to refer to.
     */
    public Modifier( Specification specification )
    {
        setSpecification( specification );
    }

    /**
     * Creates a new <code>Modifier</code> instance.
     *
     * @param id The object identifier.
     * @param value The modifier value.
     * @param type The type of the modifier.
     */
    public Modifier( String id, float value, ModifierType type )
    {
        setId( id );
        setType( type );
        setValue( value );
    }

    /**
     * Creates a new <code>Modifier</code> instance.
     *
     * @param id The object identifier.
     * @param value The modifier value.
     * @param type The type of the modifier.
     * @param source The source <code>FreeColObject</code>.
     */
    public Modifier( String id, float value, ModifierType type,
                     FreeColObject source )
    {
        this( id, value, type );
        setSource( source );
    }

    /**
     * Creates a new <code>Modifier</code> instance.
     *
     * @param id The object identifier.
     * @param value The modifier value.
     * @param type The type of the modifier.
     * @param source The source <code>FreeColObject</code>.
     * @param modifierIndex The modifier index.
     */
    public Modifier( String id, float value, ModifierType type,
                     FreeColObject source, int modifierIndex )
    {
        this( id, value, type, source );
        setModifierIndex( modifierIndex );
    }

    /**
     * Creates a new <code>Modifier</code> instance from another.
     *
     * @param template A <code>Modifier</code> to copy.
     */
    public Modifier( Modifier template )
    {
        copyFrom( template );
        setType( template.getType( ) );
        setValue( template.getValue( ) );
        setIncrementType( template.getIncrementType( ) );
        setIncrement( template.getIncrement( ) );
        setModifierIndex( template.getModifierIndex( ) );
    }

    /**
     * Creates a new <code>Modifier</code> instance from another with
     * an identifier override.
     *
     * @param id The object identifier.
     * @param template A <code>Modifier</code> to copy.
     */
    public Modifier( String id, Modifier template )
    {
        this( template );
        setId( id );
    }

    /**
     * Creates a new <code>Modifier</code> instance.
     *
     * @param xr The <code>FreeColXMLReader</code> to read from.
     * @param specification The <code>Specification</code> to refer to.
     * @exception XMLStreamException if there is an error reading the
     *     stream.
     */
    public Modifier( FreeColXMLReader xr, Specification specification ) throws XMLStreamException
    {
        setSpecification( specification );
        readFromXML( xr );
    }

    /**
     * Creates a new <code>Modifier</code> instance.
     *
     * @param e The <code>Element</code> to read from.
     * @param specification The <code>Specification</code> to refer to.
     */
    public Modifier( Element e, Specification specification )
    {
        setSpecification( specification );
        readFromXMLElement( e );
    }


    /**
     * Makes a timed modifier (one with start/end turn and increment)
     * with the specified identifier from a template modifier
     * (containing the increment and value) and given start turn.
     *
     * Currently the only suitable template is
     * "model.modifier.colonyGoodsParty".
     *
     * @param id The id for the new modifier.
     * @param template A template <code>Modifier</code> with increment.
     * @param start The starting <code>Turn</code>.
     * @return A new timed modifier.
     */
    public static Modifier makeTimedModifier( String id, Modifier template,
                                              Turn start )
    {
        Modifier modifier = new Modifier( id, template );
        float inc = template.getIncrement( );
        int duration = template.getDuration( );
        modifier.setTemporary( template.isTemporary( ) );
        // FIXME: this only works for additive modifiers
        if ( duration == 0 )
        {
            duration = ( int ) ( template.getValue( ) / - inc );
        }
        modifier.setIncrement( template.getIncrementType( ), inc, start,
                               new Turn( start.getNumber( ) + duration ) );
        return modifier;
    }

    /**
     * Get the modifier type.
     *
     * @return The <code>ModifierType</code>.
     */
    public final ModifierType getType( )
    {
        return modifierType;
    }

    /**
     * Set the modifier type.
     *
     * @param modifierType The new <code>ModifierType</code> value.
     */
    public final void setType( final ModifierType modifierType )
    {
        this.modifierType = modifierType;
    }

    /**
     * Get the modifier value.
     *
     * @return The modifier value.
     */
    public final float getValue( )
    {
        return value;
    }

    /**
     * Get the value the modifier during the given Turn.
     *
     * @param turn The <code>Turn</code> to check.
     * @return The turn-dependent modifier value.
     */
    public final float getValue( Turn turn )
    {
        if ( appliesTo( turn ) )
        {
            if ( hasIncrement( ) )
            {
                float f = ( turn.getNumber( ) - getFirstTurn( ).getNumber( ) )
                        * increment;
                return apply( value, f, incrementType );
            }
            else
            {
                return value;
            }
        }
        else
        {
            return 0;
        }
    }

    /**
     * Set the modifier value.
     *
     * @param value The new value.
     */
    public final void setValue( final float value )
    {
        this.value = value;
    }

    /**
     * Does this modifier have an increment?
     *
     * @return True if this modifier has an increment.
     */
    public final boolean hasIncrement( )
    {
        return incrementType != null;
    }

    /**
     * Get the increment type.
     *
     * @return The increment <code>ModifierType</code>.
     */
    public final ModifierType getIncrementType( )
    {
        return incrementType;
    }

    /**
     * Set the increment type.
     *
     * @param incrementType The new increment <code>ModifierType</code>.
     */
    public final void setIncrementType( final ModifierType incrementType )
    {
        this.incrementType = incrementType;
    }

    /**
     * Get the increment value.
     *
     * @return The increment value.
     */
    public final float getIncrement( )
    {
        return increment;
    }

    /**
     * Set the increment value.
     *
     * @param increment The new value.
     */
    public final void setIncrement( final float increment )
    {
        this.increment = increment;
    }

    /**
     * Set the whole increment.
     *
     * @param incrementType The new <code>ModifierType</code>.
     * @param increment The new increment value.
     * @param firstTurn The first <code>Turn</code> the increment is
     *     active.
     * @param lastTurn The last <code>Turn</code> the increment is
     *     active.
     */
    public final void setIncrement( final ModifierType incrementType,
                                    final float increment,
                                    Turn firstTurn, Turn lastTurn )
    {
        if ( firstTurn == null )
        {
            throw new IllegalArgumentException( "Null firstTurn" );
        }
        this.incrementType = incrementType;
        this.increment = increment;
        setFirstTurn( firstTurn );
        setLastTurn( lastTurn );
    }

    /**
     * Get the modifier index.
     *
     * @return The modifier index.
     */
    public final int getModifierIndex( )
    {
        return modifierIndex;
    }

    /**
     * Set the modifier index.
     *
     * @param modifierIndex The new modifier index value.
     */
    public final void setModifierIndex( final int modifierIndex )
    {
        this.modifierIndex = modifierIndex;
    }

    /**
     * Applies the given value to the given base value, depending on
     * the type of this Modifier.
     *
     * @param base a <code>float</code> value
     * @param value a <code>float</code> value
     * @return a <code>float</code> value
     */
    public float apply( float base, float value )
    {
        return apply( base, value, getType( ) );
    }

    /**
     * Applies the given value to the given base value, depending on
     * the give modifier Type.
     *
     * @param base The base value.
     * @param value The modifier value.
     * @param type The <code>ModifierType</code>.
     * @return The result of applying the value to the base.
     */
    private float apply( float base, float value, ModifierType type )
    {
        switch ( type )
        {
            case ADDITIVE:
                return base + value;
            case MULTIPLICATIVE:
                return base * value;
            case PERCENTAGE:
                return base + ( base * value ) / 100;
            default:
                return base;
        }
    }

    /**
     * Applies this Modifier to a number. This method does not take
     * scopes, increments or time limits into account.
     *
     * @param number a <code>float</code> value
     * @return a <code>float</code> value
     */
    public float applyTo( float number )
    {
        return apply( number, value );
    }

    /**
     * Applies this Modifier to a number.  This method does take
     * increments into account.
     *
     * @param number The number to modify.
     * @param turn The <code>Turn</code> to evaluate increments in.
     * @return The modified number.
     */
    public float applyTo( float number, Turn turn )
    {
        return ( incrementType == null ) ? apply( number, value )
                : apply( number, getValue( turn ), getType( ) );
    }

    // @compat 0.10.7

    /**
     * Helper for scope fixups.
     *
     * @return True if a negated person scope was added.
     */
    public boolean requireNegatedPersonScope( )
    {
        if ( hasScope( ) ) return false;
        addScope( Scope.makeNegatedPersonScope( ) );
        return true;
    }
    // end @compat 0.10.7


    // Override FreeColObject

    /**
     * {@inheritDoc}
     */
    @Override
    public int compareTo( FreeColObject other )
    {
        int cmp = 0;
        if ( other instanceof Modifier )
        {
            Modifier modifier = ( Modifier ) other;
            cmp = modifierIndex - modifier.modifierIndex;
            if ( cmp == 0 )
            {
                cmp = modifierType.ordinal( ) - modifier.modifierType.ordinal( );
            }
            if ( cmp == 0 )
            {
                cmp = FreeColObject.compareIds( getSource( ),
                                                modifier.getSource( ) );
            }
        }
        if ( cmp == 0 ) cmp = super.compareTo( other );
        return cmp;
    }


    // Override Object

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals( Object o )
    {
        if ( o == this ) return true;
        if ( o instanceof Modifier )
        {
            Modifier m = ( Modifier ) o;
            return Utils.equals( this.modifierType, m.modifierType )
                    && this.value == m.value
                    && this.increment == m.increment
                    && Utils.equals( this.incrementType, m.incrementType )
                    && this.modifierIndex == m.modifierIndex
                    && super.equals( o );
        }
        return false;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode( )
    {
        int hash = super.hashCode( );
        hash = 31 * hash + Float.floatToIntBits( value );
        hash = 31 * hash + Float.floatToIntBits( increment );
        hash = 31 * hash + Utils.hashCode( modifierType );
        hash = 31 * hash + Utils.hashCode( incrementType );
        return 31 * hash + modifierIndex;
    }


    // Serialization

    private static final String INCREMENT_TAG = "increment";
    private static final String INCREMENT_TYPE_TAG = "increment-type";
    private static final String INDEX_TAG = "index";
    private static final String TYPE_TAG = "type";
    // @compat 0.11.3
    private static final String OLD_INCREMENT_TYPE_TAG = "incrementType";
    // end @compat 0.11.3


    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeAttributes( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeAttributes( xw );

        xw.writeAttribute( VALUE_TAG, value );

        xw.writeAttribute( TYPE_TAG, modifierType );

        if ( incrementType != null )
        {
            xw.writeAttribute( INCREMENT_TYPE_TAG, incrementType );

            xw.writeAttribute( INCREMENT_TAG, increment );
        }

        if ( modifierIndex >= 0 )
        {
            xw.writeAttribute( INDEX_TAG, modifierIndex );
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        modifierType = xr.getAttribute( TYPE_TAG, ModifierType.class,
                                        ( ModifierType ) null );

        value = xr.getAttribute( VALUE_TAG, UNKNOWN );

        // @compat 0.11.3
        if ( xr.hasAttribute( OLD_INCREMENT_TYPE_TAG ) )
        {
            incrementType = xr.getAttribute( OLD_INCREMENT_TYPE_TAG,
                                             ModifierType.class,
                                             ( ModifierType ) null );
            increment = xr.getAttribute( INCREMENT_TAG, UNKNOWN );
            // end @compat 0.11.3
        }
        else if ( xr.hasAttribute( INCREMENT_TYPE_TAG ) )
        {
            incrementType = xr.getAttribute( INCREMENT_TYPE_TAG,
                                             ModifierType.class,
                                             ( ModifierType ) null );

            increment = xr.getAttribute( INCREMENT_TAG, UNKNOWN );
        }
        else
        {
            incrementType = null;
            increment = 0;
        }

        modifierIndex = xr.getAttribute( INDEX_TAG, DEFAULT_MODIFIER_INDEX );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString( )
    {
        StringBuilder sb = new StringBuilder( 64 );
        sb.append( "[Modifier " ).append( getId( ) );
        if ( getSource( ) != null )
        {
            sb.append( " (" + getSource( ).getId( ) + ")" );
        }
        sb.append( " " ).append( modifierType )
                .append( " " ).append( value );
        if ( modifierIndex >= DEFAULT_MODIFIER_INDEX )
        {
            sb.append( " index=" ).append( modifierIndex );
        }
        List< Scope > scopes = getScopes( );
        if ( ! scopes.isEmpty( ) )
        {
            sb.append( " [" );
            for ( Scope s : scopes ) sb.append( " " ).append( s );
            sb.append( " ]" );
        }
        sb.append( "]" );
        return sb.toString( );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getXMLTagName( ) { return getXMLElementTagName( ); }

    /**
     * Gets the XML tag name for this element.
     *
     * @return "modifier".
     */
    public static String getXMLElementTagName( )
    {
        return "modifier";
    }
}
